In the steel industry, large circular saws are commonly used for cutting steel blooms, billets and tubes in a variety of sizes and shapes. Carbon and alloy steel in particular present a harsh environment for saw blades. Saw blades for such cutting operations are expensive to replace. Significant time and attention is devoted to optimizing the life of the saw blades. Traditionally, manufacturers of saw blades for cutting carbon and alloy steels have recommended a constant blade speed (revolutions per minute or RPM) and feed rate (inches per minute or IPM), in order to achieve a constant chip load. A typical chip loading is 0.004 inch, meaning that every tooth on the blade takes a 0.004 “chip” from the workpiece. Depending on the manufacturer and the blade, a manufacturer will typically provide a chart specifying the RPM and IPM for a various grades of steel, which in theory produce the desired, or optimum, chip load. Notwithstanding these efforts by the blade manufacturers, inconsistencies continue to exist between the blade life, the cutting cycle time and production costs for different grades of steel.
The cycle time is defined as the amount of time to complete one cut for a given workpiece. For example, a twelve inch round bloom may take from 147 to 189 seconds to complete one cut under the normal recommended chip load. This is an important statistic in the production management, since higher cycle time, results in slower production. Buffer zones are filled with cut rounds to be processed in a hot mill, so that manufacturing harder grades of steel does not interrupt production on the hot mill. If cycle time does not remain predictably constant, costly interruptions and down time may result.
Maintaining constant cycle time does not solve the problem of optimizing blade life, however, since by maintaining both constant blade speed and feed rate (RPM and IPM) causes) variable loading on the blade due to other variables, particularly the grade or hardness of the steel. Thus there is a need for a method of optimizing the blade loading in order to minimize wear and stresses.